Close

We are using cookies to give you the best experience on our site. Cookies are files stored in your browser and are used by most websites to help personalise your web experience.

By continuing to use our website without changing the settings, you are agreeing to our use of cookies.

Find out more
You are here:
> > > > How does the shoulder work?

How does the shoulder work?

Your shoulder is the most mobile joint in your body. This is because your main shoulder joint (the glenohumeral joint) is a ball-and-socket joint.  Ball-and-socket joints allow for the most amount of movement of all the different types of joints in your body.

Ball-and-socket joints get this name because the ball-shaped upper arm bone (the humerus) fits into the cup-like hollow of the top part of your shoulder blade bone (the scapula).

Your shoulder joint is surrounded by a tough fibrous sleeve, called the capsule, which helps to hold the joint together. The inner layer of the capsule (the synovium) produces a fluid which nourishes the cartilage and lubricates the joint so it moves more smoothly. A group of four muscles and their tendons make up the rotator cuff, which controls movement and also helps to hold the joint together.

There’s also a smaller joint (the acromioclavicular joint) where the top of your shoulder blade meets your collarbone, above the main shoulder joint.

Main features of the shoulder

For more information, go to www.arthritisresearchuk.org.
Arthritis Research UK fund research into the cause, treatment and cure of arthritis. You can support Arthritis Research UK by volunteering, donating or visiting our shops.